Abstract:

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Targeting of drugs and therapeutic materials to target cells or designated
intracellular locations relies upon their cellular / sub-cellular targeting and trafficking. The ideal optical properties of quantum dots offer the possibility of using them as fluorescent probes to study the intracellular uptake and pathway of drugs or biomolecules. Quantum dots, ZnS coated CdSe, were synthesized and successfully incorporated into polystyrene (PS) particles grafted with carboxyl groups and folic acid was attached to the nanoparticle surfaces. The nanocomposites were monodisperse and highly luminescent, and their intracellular uptake to cancer cells was investigated using confocal microscopy.

Abstract: This study was conducted to explore the effect of CuO nanoparticles (NPs) on the cell membrane permeability and its exclusion from cells. Human A549 lung cells were exposed to 5mg/L and 15mg/L CuO NPs. Cell membrane permeability was evaluated in 2h and 4h. After 4 hours exposure, the membrane was damaged. Exclusion of copper from cells after 24h exposure with 5mg/L and 15 mg/L CuO NPs are time and dose dependent. And the cell viability was resumed gradually. It is concluded that CuO NPs could induce cytotoxicity, and destroy the membrane integrity. One detoxify mechanism was the exclusion of excessive copper from cells themselves.

Abstract: The medicinal plant Scutellaria baicalensis Georgi has been used widely in traditional Chinese medicine for anti-inflammation, anticancer, antiviral and antibacterial infections, reducing the total cholesterol level and decreasing blood pressures. Baicalein and baicalin are two major flavonoid of Scutellaria baicalensis Georgi, exhibit various bioactivities. In the present study, the stimulatory activity of baicalin and baicalein derived from Scutellaria baicalensis on insulin secretion in vitro was investigated using HIT-T15 cell, a Syrian hamster transformed β-cell line. The survival rate of cells treated with baicalin or baicalein (0.01-0.5 mg/ml) increased significantly (P < 0.05). In the presence of 5.6 mM glucose, baicalin or baicalein (0.01-0.5 mg/ml) increased glucose-stimulated insulin secretion and cellular ATP levels in HIT-T15 cells. Baicalin and baicalein exhibited significant stimulatory activity in a dose-dependent manner without apparent cytotoxicity at concentrations less than 0.1 mg/ml. The results obtained in this study suggest that baicalin or baicalein increases the insulin secretion of HIT-T15 cells by the enhancement of β-cells activity and cellular ATP levels. Baicalin or baicalein could be candidates for a new class of anti-diabetic drugs.

Abstract: Although effective, chemotherapeutic drugs often cause undesired side-effects. Thus, encapsulating chemotherapeutic drugs into nanoscale drug delivery vehicles (DDVs) has the potential to reduce side effects and promote targeted delivery. By mimicking ABA like block-co-polymer systems, we have developed a new amphiphilic biomimetic co-polymer Boc-Ile-PEG-Ile-Boc which was found to readily self-assemble into nanomicelles within hydrophilic shell structures. To facilitate targeting tumor cells, the nanoassemblies were bound to folate, leading to the formation of core shell like structures (IBP-F). Gold nanoparticles (AuNPs), were then embedded followed by functionalization with a second layer of folate. The final DDV system abbreviated (IBP-F-Au-F) formed a multi-layered nanostructure that was capable of efficiently encapsulating the anti-tumor drug tamoxifen. For comparison, we also examined the efficacy of the IBP-F assemblies as DDVs in the absence of AuNPs and a second folate layer. Release profiles showed an initial burst release, followed by sustained release. The DDVs were found to be biocompatible. Upon encapsulating the DDVs with tamoxifen, cell proliferation was inhibited over a period of 72 hours for both DDVs, while non-cancerous dermal fibroblasts continued to proliferate, thus indicating specific targeting ability of the DDVs. Confocal microscopy studies conducted in the presence of human breast cancer cells, MDA-MDB 231 revealed that the drug loaded assemblies were successfully internalized within the cells. SPR analysis demonstrate that IBP-F-Au-F had a higher affinity for breast cancer cells over non-cancerous keratinocyte cells. Thus, we have developed a new family of DDVs that selectively targets tumor cells.